20-alkoxy-delta20-21-carboxaldehydes of the pregnane series and method of preparing the same



product by filtration.

United States Patent This invention relates to new steroid compounds. More particularly it relates to ZO-lower alkoxy-A 21- ca-rboxaldehyde-s of the pregnane series and methods of preparing the same.

The novel steroids of the present invention illustrated by the following formula:

may be where R is lower alkyl, R is selected from the group consisting of hydrogen and lower alkanoyl, C -C is a trivalent radical selected from the group consisting of Ell-lower alkyl and C -C is a divalent radical selected from the group consisting of 0 ll C3; V /CE QC-lowcr alkyl Cr CH an CH The novel process of this invention consists of reacting an appropriate steroid having at the 17-position an acetyl group with a trialkylorthoformate in the presence of an acid such as perchloric acid or fluoroboric acid. Ordinarily the reaction is carried out by adding in excess of one equivalent of aqueous perchloric acid (e.g., 72% V perchloric acid) or fluoroboric acid, usually at a rate of rapid dropping, to a vigorously stirred suspension of steroid in an excess of trialkylorthoforrnate. Generally, the reaction is substantially complete after 5-15 minutes of stirring after the addition of the designated acid, and the product may be recovered, after neutralization with an acid acceptor such as pyridine, by pouring the neutralized reaction mixture into water and collecting the Purification of the product may usually be achieved by direct crystallization although in some cases intermediate purification techniques such as chromatography may be necessary. It is generally convenicnt to carry out the reaction at approximately room 3,201,425 Patented Aug. 17, 1965 "ice temperature, but higher temperatures may occur as a result of theexotherrnic characteristic of the reaction process.

There is evidence that. the course of the novel reaction of this inventionincludes formation of an intermediate perchlorate or fluoroborate 'salt. For the purpose of this invention, however, no emphasis need be given to this since the intermediates are unstable, and are not isolated when the reaction is run for preparative purposes.

A very wide variety of starting steroid-s may be used in carrying out the process of this invention, it being necessary only that there be a ZO-keto function. Functional groups elsewhere in the steroid molecule which are sensitive to trialkylorthoformates will of course react appropriately during the intended reaction unless such groups are blocked.

Among the starting steroids which have been found useful for the novel reaction of this invention are the follownig: 3,B-acetoxypregn-S-en-ZO-one; 3,8-hydroxypregn-S-en-ZO-one; 3fl-acetoxy-l6a-methylpregn-5-en-20 one; 3fi-acetoxyallopregnan- 20 one; 3,8-hydroxyallopregnan-ZO-one; 3B-acetoxypregnan-20-one; 3B-acetoxy-6- methylpregn-S-en-ZO-one; 3a,6a-diacetoxypregnan-2O-one; 3a,l2a-diacetoxypregnan 20 one; 3,3-dimethoxypregn- 11-en-20-one and the like.

The reaction by which 20-lower alkoxy-A -2l-carboxaldehyde steroids may be converted into their corresponding etianic esters consist of a permanganate oxidation. The steroid is dissolved in a suitable solvent such as acetone, and an excess of permanganate salt (e.g., potassium permanganate) is added. The mixture is stirred for 2 hours, more or less, and vwater is added. The reaction mixture is cooled, and sulfur dioxide is bubbled through the mixture until excess permanganate is reduced. The acetone is removed by evaporation under reduced pressure, and the resulting suspension is poured into water. The product is collected by filtration and crystallized from an appropriate solvent system. The utility of etianic esters is described by Fieser and Fieser in their book entitled, Steroids, page 610 (chart 5) Compound I, which is shown as convertible into deoxycorticosterone acetate. The 2O-lower alkoxy-A -2Lcarboxaldehydes of the pregnane series in themselves have utility as hypocholesteremic agents, and therefore are useful in the treatment of vascular disorders.

Example 1.P reparati0n of .ifi-acetoxy-Zl-formyl- 20-methoxypregna-5,20-di0ne A suspension of 10 grams of 3li-acetoxy-5-pregnen 20- one in milliliters of trimethylorthoformate is stirred vigorously, and 4.7 milliliters (2.1 equivalents) of 72% perchloric acid is added at a rapid rate of dropping. After addition is complete, the reaction mixture is stirred for 10 minutes, after which 5 milliliters of pyridine is added, and the entire mixture is poured into water. The product is collected by filtration and recrystallized from acetonepetroleum ether, melting point l87-189 C.

' In a further experiment carried out as above, concentrated fluoroboric acid is substituted for perchloric acid to give the product of the example.

Example 2.--P reparati0n of .i'fi-acetoxy-ZO-thoxy- 21-f0rmylpregna-5,20-diene Following the procedure of Example 1, and substituting triethylorthoformate for trimethylorthoformate the product 3fi-acetoxy-20-ethoxy-21-formyl-pregna-5,20-diene is obtained, melting point 178 C.

pregne-ZO-one the product 2l-formyl-3 8,20dimethoxypregna-5,20'diene is obtained, melting point 144l45 C.

Example 4.-Preparatin of 3,8-acet0xy-21-f0rmyl-20- methoxy-I 6 a-metlzyl pregna- ,ZO-di ene When the procedure of Example 1 is followed and 3/8- acetoxy-l6a-methyIpregn-S-en-20-one is used in place of 3fi-acetoxy-5-pregnen-20-one, the product 3,8-acetoxy-2lformyl 20 methoxy-l6a-rnethylprcgna-5,20-diene is obtained, melting point 204-206 C.

Example 5.Preparati0n of 3fi-acet0xy-Z1-f0rmyl-20- etl10xy-16a-met/zylpregna-5,20-diene Following the procedure of Example 1 and substituting 3,8-acetoxy-l6a-methylpregn-S-en-ZO-one for 3,B-acetoxy 5-pregnen-20-one and triethylorthoformate for trimethylorthoformate there is obtained 3fiacetoxy-21-formyl-20- ethoxy-16a-methylpregna-5,20-diene, melting point 203- 205 C.

Example 6.--Preparati0n of jfl-acetoxy-ZI-formyl- 20-metlzoxyallopregn-ZO-ene Using the procedure described in Example 1 and substituting 3e-acetoxyallopregnan-ZO-one for SB-acetoXy-S- pregnen 20- one the product 3,8-acetoxy-21-formyl-20- methoxyallopregn-ZO-ene is obtained, melting point 191- 192 C.

Example 7.-Preparati0n of 3fi-acet0xy-21-f0rmyl- ZO-ethoxyallopregn-ZO-ene When 3li-acetoxyallopregnan-ZO-one and triethylorthoformate are reacted as in Example 1, the product is 3,8- acetoxy 20 ethoxy-Zl-formylallopregn-20-one, melting point 126-127 0.

Example 8.Preparati0n 0f (1) 2]-formyl-20-meth0xy- Following the procedure of Example 1 and substituting 3,B-hydroxyallopregnan-ZO-one for 3/3-acetoxy-5-pregnen- 20-one gives after chromatographic separation 21-formyl- 20-methoxyallopregna-2,30-diene, melting point 186- 187 C.; 21 formyl-3B-formyloxy-20-methoxyallopregn- ZO-ene, melting point 136137 C.; and 2l-formyl-20- methoxyallopregn-20-en-3B-ol, melting point 227 229 Example 9.Preparati0n of 3B-acet0xy-21-f0rmyl- 20-methoxypregn-ZO-ene When the procedure of Example 1 is followed and 3eacetoxypregnan-ZO-one is substituted for 3e-acetoxy-5- pregnen-ZO-one, the product obtained is 3/3-acetoxy-2lformyl 20 methoxypregn-ZO-ene, melting point 137- 138 C.

Example 10.Preparati0n 0f 3,8-acet0xy-21-f0rmyl- 20-meth0xy-6-methylpregna-5,20-diene Using the procedure described in Example 1 and sub stituting 3fi-acetoxy-6-methylpregn-5-en-20-one for 3;?- acetoxy 5 pregnen-ZO-one, the product 3B-acetoxy-2lformyl-20-methoxy 6 methylpregna-5,20-diene is obtained, melting point 155l56 C.

Example 11.Preparati0n of 3a,6a-diacet0xy-21- formyl-20-metlzoaq pregn-ZO-ene Substituting 3a,6a-diacetoxy-20-one for 3fl-acetoxy-5- pregnen-ZO-one in the process of Example 1, plOdllCCS 3a,6a-diacetoxy-21-formyl-20-methoxypregn-ZO-ene.

Example 12.Preparati0n of 3a,12a-diacet0xy-21- f0rmyl-20-methoxypregn-ZO-ene Using the procedure of Example 1 and substituting 3a,l2a-diacetoxypregn-20-one for Sfi-acetoxy-S-pregnen- 20-one, the product 3a,l2a-diacetoxy-2l-formyl-ZO-methoxyprcgn-20-ene is obtained.

Example 13.Preparati0n of 21-f0rmyl-3,3,20- trimethoxypregna-J 1 ,2 O-diene Following the procedure of Example 1 and substituting 3,3-dimethoxypregn-ll-en-20-one for 3B-acetoxy-5-pregnen 20 one, the product 21-formyl-3,3,20-trirnethoxypregna-l1,20-diene is obtained.

Example 14.Preparation of 21-f0rmyI-20-melhoxypregna-S,20-dien-3fi-0l When 3;? acetoxy-Z1-formyl-20-methoxypregna-5,20- diene is hydrolyzed with sodium methoxide in methanol, the product 2l-formyl 20 methoxypregna-SJO-dien-Stiol, melting point 208-209 C. is obtained.

Example 15.Preparati0n of 20-etlzoxy-2I-formylpregna-5,20-dien3fi-0l Hydrolyzing 3,9 acetoxy-ZO-ethoxy-Zl-formylpregna- 5,20-diene with sodium methoxide in methanol gives 20- ethoxy 21 formylpregna-S,20-dien-3fi-ol, melting point l9l-l92 C.

Example 16.Preparari0n of 3p-acet0xy-17ficarbamethoxyandrost-S-ene Example 17.-Preparati0;z of 3B-acel0xy-I7/3- tcar boethoxyandrost-S-ene Following the procedure of Example 16 and using 3,8- acetoxy-ZO-ethoxy-Zl-formylpregna-5,20-diene in place of 3fi-acetoxy-21-formyl-20 methoxypregna-5,20-diene the product 3,8-acetoxy-17,3-carboethoxyandrost-S-ene, melting point l132 C. is obtained.

Example I8.Preparati0n 0f 3,8-acet0xy-l 713- carbometlzoxyandrostane Using the process of Example 16 and substituting 3B- acetoxy-21-formyl20 methoxypregn-ZO-ene in place of 3fi-acetoxy-2Jl-formyl-2O methoxypregna-5,20-diene, the product 3p-acetoxy-17fl-carbomethoxyandrostane, melting point l39l40 C.

Example 19.Ireparati0n of 1718- carbometlzoxyandrostand-0ne When the process of Example 16 is followed and 21- f0rmyl-3B-hydroxy-ZO-methoxyallopregnene is substituted for 3,8-acetoxy-2l-formyl ZO-methoxypregna-5,20-diene, the product 17B-carbomethoxyandr0stan-3-one, melting point 171172 C. is obtained.

We claim:

1. A steroid of the formula:

wherein R is lower alkyl, R is selected from the group consisting of hydrogen and lower alkanoyl, C -C is a trivalent radical selected from the group consisting of (5 (ll-lower alkyl and C C is a divalent radical selected from the group consisting of CH, CH O 0%; C and (P -lower alkyl I I (511 CE;

2. The compound 3B-acetoxy-20 ethoxy-21-formylpregna-5,20-diene.

3. The compound 21-f0rmyl-35,20-din1ethoxypregna- 5,20-diene.

4. The compound 3,8-acetoXy-21-formyl-20-methoxy- 16a-methylpregna-5,20-diene.

5. The compound 3fl-acetoxy-20-ethoXy-2A1-formy1-16amethylpregna5,20-diene.

6. The compound 3,8-acetoxy-21 formyl-ZG-methoxyallopregn-ZO-ene.

7. The compound 3fl-acetoxy-21 formyl-ZO-methoxypregn-ZO-ene.

8. The compound 3fi-acetoxy-21 formyl-ZO-methoxy- 6-methylpregna-5,20 diene.

9. The compound 301,60: diacetoXy-21 formyl-20 methoxypregn-ZO-ene.

10. The compound 3a,12u-diacetoxy-21 formyl-ZO- methoxypregn-ZO-ene.

11. The compound 21-formyl-3,3,20-trimethoxypregna- 1 1,20-diene.

12. The compound 21-formyl-ZO-methoxypregna-5,20 dien-3fl-ol.

13. The compound 20-ethoxy-2l formylpregna-5,20- dien-3p3-ol.

14. A method of preparing a steroid of the formula:

and

6 (3 -lower alkyl and C -C is a divalent radical selected from the group consisting of CH: CH and (P -lower alkyl 1 an a which comprises contacting the corresponding 17-acetyl steroid with a tri(lower)alkylorthoformate in the presence of an acid selected from the group consisting of perchloric acid and fluoroboric acid and recovering said product therefrom.

15. A method of preparing SB-acetoxy-ZO-methoxy-Z1- formylpregna-5,20-diene which comprises contacting 3B- acetoxy-S-pregnen-ZO-one with trimethylorthoformate in the presence of perchloric acid and recovering said compound therefrom.

16. A method of preparing 3fl-acetoxy-17fi-carbomethoxyandrost-S-en which comprises contacting 3;8-acetoxy- S-pregnen-ZO-one with trimethylorothoformate in the presence of perchloric acid and subsequently treating the reaction product with potassium permanganate and recovering said compound therefrom.

17. A method of preparing 3B-acetoxy-17/8carbomethoxyandrostane which comprises contacting 35-acetoxypregnan-ZO-with trimethylorthoformate in the presence of perchloric acid and subsequently treating the reaction product with potassium permanganate and recovering said compound therefrom.

References Cited by the Examiner UNITED STATES PATENTS LEWIS GO'ITS, Primary Examiner. 

1. A STEROID OF THE FORMULA:
 16. A METHOD OF PREPARING 3B-ACETOXY-17B-CARBOMETHOXYANDROST-5-EN WHICH COMPRISES CONTACTING 3B-ACETOXY5-PREGNEN-20-ONE WITH TRIMETHYLOROTHOFORMATE IN THE PRESENCE OF PERCHLORIC ACID AND SUBSEQUENTLY TREATING THE REACTION PRODUCT WITH POTASSUM PERMANGANATE AND RECOVERING SAID COMPOUND THEREFROM. 